Process of making nutritive extracts from yeast.



I NITED STATES PATENT OFFICE.

RICHARD RUOKFORTH, or STETTIN, GERMANY.

PROCESS OF MAKING NUTRITIVE EXTRACTS FRoM YEAs-r.

SPECIFICATION forming part Of Letters Patent No. 648,468, dated May 1,1900.

Application filed March 31, 1899. Serial No, 711 256. (No specimens.)

To all whom it may concern:

Be it known that I, RICHARD RiicKFoRTH, residing at Stettin, Germany,have invented certain new and useful Improvements in or Relating to theTreatment of Yeas t, (for which I have made application'for LettersPatent in Great Britain under N0. 4, 709, dated March 3, 1899,) of whichthe following is a specification.

As is known, it is possible in accordance with the experiments of Pictetand Yung to expose yeast to intense cold without injuring its vitality.In fact, microscopical investigations have disclosed no visible changes.

In my experiments I have found that yeast in a frozen state whensuddenly or rapidly heated loses its vitality, the cells bursting attemperatures which are below that at which the protein substancescontained therein coagulate. There is, therefore, here a simple means ofsecuring the cell contents specially rich in protein substances in fargreater quantities than can be obtained by means of other methods, forin the latter the temperatures required are so high that the total orpartial coagulation of the protein matter cannot be avoided. Thisprocess, therefore, consisting in first congealing the yeast, thendestroying its vitality by a sudden raising of temperature in order toobtain the contents of the cells, forms the principal object of myinvention.

The process itself is very simple. After having washed-and cleaned theyeast it is exposed in suitable vessels for such a length of time to atemperature below 0 centigrade (32 Fahrenheit) as to congeal it.Refrigeratingqnachines may be advantageously used for this purpose. .Itis advisable to subject the yeast to a freezing temperature of, say, -12to 15 centigrade for a time, so that the yeast will congeal into a hardmass, which can afterward be crushed. The yeast having arrived at thelatter state, the required amount of heat must be rapidly supplied. Thiscan be done in the following manner: The yeast after having been crushedis heated to the required temperature (which may vary according toulterior purposes) by Water of the desired temperature. The yeast'cellsare thereby destroyed or broken. The same effect is likewise secured byfirst crushing the frozen mass between ordinary crushing-rollers andafterward passing it over or between heated cylinders, such as areemployed in cardboard or glazing machines. The cylinders may be replacedby heated plates or any other device serving the purpose. To obtain theprotein of the mass after it has thus been heated, 'it is pressed or theprotein is lixiviated by Water at a temperature at which the proteincontained in the yeast does not coagulate, the admixture of a smallquantity of some acid being of great advantage, inasmuch as it preventsdecomposition of the protein. It is also possible at this stage of theprocess to treat the mass with proteolytic ferments, which will, theyeast-cells being destroyed or burst, digest the albumen moreenergetically than when the ferments are added to untreated yeast,treating the yeast directly at a temperature of, say, 38 centigrade withpepsine and hydrochloric acid.

. I claim- 1. The process of treating yeast consisting in freezing themass, and subjecting the same to asudden increase of temperature,whereby the yeast-cells are burst without coagulating their contents,substantially as set forth;

2. The process of treating yeast consisting in freezing the mass, thendividing the same and finally subjecting the divided particles to asudden increase of temperature, whereby the yeast-cells are burstwithout coagulation of the contents of said cells.

3. A process for the treatment of yeast, consisting in congealing theyeast, rapidly heating to a temperature of about 42 centigrade todestroy the cells, and then adding proteolytic ferlnents.

In testimony that I claim the foregoing as my invention I have signed myname in presence of two subscribing witnesses.

RICHARD RiioKFoR'rn.

